Siemens Simatic ET 200S Operating Instructions Manual page 322

Glossary
Power modules
Power modules monitor the voltage supply for all electronic modules within the voltage
group. The supply voltage for the voltage group is fed in via the terminal module TM-P
Prewiring
The wiring of the terminal modules before the electronic modules are inserted.
Process image
The process image is a component of the system memory of the DP master. The signal
states of the input modules are transferred to the process-image inputs at the beginning of
the cyclic program. At the end of the cyclic program, the values of the process-image outputs
are transferred to the DP slave as the signal states.
PROFIBUS
PROcess FIeld BUS, Process and fieldbus standard, defined in the IEC 61784-1:2002
Ed1 CP 3/1 standard. It defines functional, electrical, and mechanical properties for a bit-
serial field bus system.
PROFIBUS is available with the protocols DP (= distributed peripherals, that is, distributed or
remote IO), FMS (= field bus message specification), PA (= process automation), or TF
(= technological functions).
PROFIBUS address
Each bus node must receive a PROFIBUS address to identify it uniquely on the PROFIBUS.
The PC/programming device has the PROFIBUS address "0".
PROFIBUS addresses 1 to 125 are permissible for the ET 200S distributed IO system
PROFINET
Within the context of Totally Integrated Automation (TIA), PROFINET is the systematic
continuation of the following systems:
• PROFIBUS DP, the established field bus
• Industrial Ethernet, the communication bus for the cell level
Experiences from both systems have been and are being integrated in PROFINET.
As an Ethernet-based automation standard of PROFIBUS International (formerly PROFIBUS
user organization, registered society) PROFINET thus defines a communication, automation
and engineering model valid for all manufacturers.
Glossary-6
Operating Instructions, 12/2005, A5E00515771-03
ET 200S